The invention relates to an apparatus for individually separating stacked printed products and more particularly to an apparatus for separating printed products which uses a plurality of suction heads arranged on a rotor.
U.S. Pat. No. 5,169,285 and corresponding EP A1 0 332 828 describe an apparatus for individually separating stacked sheets of paper. The disclosed apparatus, is designed as a rotary feeder which includes a plurality of satellites arranged in a rotor. The satellites rotate about their own axis during the rotation of the rotor. They have drum sheaves, which are spaced from one another and between which suction heads are arranged. The rotor is located underneath a feeder magazine for receiving the stack. The drum sheaves of the satellites roll on the underside of the stack, so that the lowermost sheet, seized and temporarily held securely at the fold by the suction heads, is wound around the drum sheaves. The sheet is first drawn into a conveying nip which is formed at each satellite between the central drum sheaf and an endless conveyor belt which wraps partially around the central drum sheaf. The sheet is then pushed out on a path leading away tangentially from the drum sheaves and through the circumference of the rotor. The rotary feeder cooperates with a transporting-away conveyor with circulating grippers. The grippers take over the sheet of paper which is ejected from each of the satellites. This, however, works only if the fold is pushed out of the conveying nip as directly as possible into the gripper. This results in the sheet being pushed outward long after the fold is seized, i.e. it is considerably compressed and must therefore bow convexly. This deformation is abruptly reversed when the trailing edge leaves the conveying nip. In the case of thick sheets the limits of this arrangement are soon reached.
U.S. Pat. No. 4,127,262 and German Offenlegungsschrift 27 32 591 also describe a roller feeder which is likewise arranged underneath a stack magazine and in which a single suction head is arranged at one end of an angle lever. The other end is guided in a linear guide, and a swivel bearing is arranged eccentrically on a planetary gear. The planetary gear is driven in a circulating manner and part is in engagement with a fixed internal gear ring. This produces an angular orbit with a number of deflecting points for the suction head. One of these deflecting points lies in the takeover region.
Therefore, it is an object of the present invention to provide an apparatus which can separate a stacked product from a neighboring stacked product quickly and reliably.